drivers/char/watchdog/advantechwdt.c

   1 /*
   2  *      Advantech Single Board Computer WDT driver
   3  *
   4  *      (c) Copyright 2000-2001 Marek Michalkiewicz <marekm@linux.org.pl>
   5  *
   6  *      Based on acquirewdt.c which is based on wdt.c.
   7  *      Original copyright messages:
   8  *
   9  *      (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
  10  *                              http://www.redhat.com
  11  *
  12  *      This program is free software; you can redistribute it and/or
  13  *      modify it under the terms of the GNU General Public License
  14  *      as published by the Free Software Foundation; either version
  15  *      2 of the License, or (at your option) any later version.
  16  *
  17  *      Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
  18  *      warranty for any of this software. This material is provided
  19  *      "AS-IS" and at no charge.
  20  *
  21  *      (c) Copyright 1995    Alan Cox <alan@redhat.com>
  22  *
  23  *      14-Dec-2001 Matt Domsch <Matt_Domsch@dell.com>
  24  *          Added nowayout module option to override CONFIG_WATCHDOG_NOWAYOUT
  25  *
  26  *      16-Oct-2002 Rob Radez <rob@osinvestor.com>
  27  *          Clean up ioctls, clean up init + exit, add expect close support,
  28  *          add wdt_start and wdt_stop as parameters.
  29  */
  30
  31 #include <linux/module.h>
  32 #include <linux/moduleparam.h>
  33 #include <linux/types.h>
  34 #include <linux/miscdevice.h>
  35 #include <linux/watchdog.h>
  36 #include <linux/fs.h>
  37 #include <linux/ioport.h>
  38 #include <linux/platform_device.h>
  39 #include <linux/init.h>
  40
  41 #include <asm/io.h>
  42 #include <asm/uaccess.h>
  43 #include <asm/system.h>
  44
  45 #define DRV_NAME "advantechwdt"
  46 #define PFX DRV_NAME ": "
  47 #define WATCHDOG_NAME "Advantech WDT"
  48 #define WATCHDOG_TIMEOUT 60             /* 60 sec default timeout */
  49
  50 static struct platform_device *advwdt_platform_device;  /* the watchdog platform device */
  51 static unsigned long advwdt_is_open;
  52 static char adv_expect_close;
  53
  54 /*
  55  *      You must set these - there is no sane way to probe for this board.
  56  *
  57  *      To enable or restart, write the timeout value in seconds (1 to 63)
  58  *      to I/O port wdt_start.  To disable, read I/O port wdt_stop.
  59  *      Both are 0x443 for most boards (tested on a PCA-6276VE-00B1), but
  60  *      check your manual (at least the PCA-6159 seems to be different -
  61  *      the manual says wdt_stop is 0x43, not 0x443).
  62  *      (0x43 is also a write-only control register for the 8254 timer!)
  63  */
  64
  65 static int wdt_stop = 0x443;
  66 module_param(wdt_stop, int, 0);
  67 MODULE_PARM_DESC(wdt_stop, "Advantech WDT 'stop' io port (default 0x443)");
  68
  69 static int wdt_start = 0x443;
  70 module_param(wdt_start, int, 0);
  71 MODULE_PARM_DESC(wdt_start, "Advantech WDT 'start' io port (default 0x443)");
  72
  73 static int timeout = WATCHDOG_TIMEOUT;  /* in seconds */
  74 module_param(timeout, int, 0);
  75 MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. 1<= timeout <=63, default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
  76
  77 static int nowayout = WATCHDOG_NOWAYOUT;
  78 module_param(nowayout, int, 0);
  79 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  80
  81 /*
  82  *      Watchdog Operations
  83  */
  84
  85 static void
  86 advwdt_ping(void)
  87 {
  88         /* Write a watchdog value */
  89         outb_p(timeout, wdt_start);
  90 }
  91
  92 static void
  93 advwdt_disable(void)
  94 {
  95         inb_p(wdt_stop);
  96 }
  97
  98 static int
  99 advwdt_set_heartbeat(int t)
 100 {
 101         if ((t < 1) || (t > 63))
 102                 return -EINVAL;
 103
 104         timeout = t;
 105         return 0;
 106 }
 107
 108 /*
 109  *      /dev/watchdog handling
 110  */
 111
 112 static ssize_t
 113 advwdt_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos)
 114 {
 115         if (count) {
 116                 if (!nowayout) {
 117                         size_t i;
 118
 119                         adv_expect_close = 0;
 120
 121                         for (i = 0; i != count; i++) {
 122                                 char c;
 123                                 if (get_user(c, buf+i))
 124                                         return -EFAULT;
 125                                 if (c == 'V')
 126                                         adv_expect_close = 42;
 127                         }
 128                 }
 129                 advwdt_ping();
 130         }
 131         return count;
 132 }
 133
 134 static int
 135 advwdt_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
 136           unsigned long arg)
 137 {
 138         int new_timeout;
 139         void __user *argp = (void __user *)arg;
 140         int __user *p = argp;
 141         static struct watchdog_info ident = {
 142                 .options = WDIOF_KEEPALIVEPING | WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
 143                 .firmware_version = 1,
 144                 .identity = WATCHDOG_NAME,
 145         };
 146
 147         switch (cmd) {
 148         case WDIOC_GETSUPPORT:
 149           if (copy_to_user(argp, &ident, sizeof(ident)))
 150             return -EFAULT;
 151           break;
 152
 153         case WDIOC_GETSTATUS:
 154         case WDIOC_GETBOOTSTATUS:
 155           return put_user(0, p);
 156
 157         case WDIOC_KEEPALIVE:
 158           advwdt_ping();
 159           break;
 160
 161         case WDIOC_SETTIMEOUT:
 162           if (get_user(new_timeout, p))
 163                   return -EFAULT;
 164           if (advwdt_set_heartbeat(new_timeout))
 165                   return -EINVAL;
 166           advwdt_ping();
 167           /* Fall */
 168
 169         case WDIOC_GETTIMEOUT:
 170           return put_user(timeout, p);
 171
 172         case WDIOC_SETOPTIONS:
 173         {
 174           int options, retval = -EINVAL;
 175
 176           if (get_user(options, p))
 177             return -EFAULT;
 178
 179           if (options & WDIOS_DISABLECARD) {
 180             advwdt_disable();
 181             retval = 0;
 182           }
 183
 184           if (options & WDIOS_ENABLECARD) {
 185             advwdt_ping();
 186             retval = 0;
 187           }
 188
 189           return retval;
 190         }
 191
 192         default:
 193           return -ENOTTY;
 194         }
 195         return 0;
 196 }
 197
 198 static int
 199 advwdt_open(struct inode *inode, struct file *file)
 200 {
 201         if (test_and_set_bit(0, &advwdt_is_open))
 202                 return -EBUSY;
 203         /*
 204          *      Activate
 205          */
 206
 207         advwdt_ping();
 208         return nonseekable_open(inode, file);
 209 }
 210
 211 static int
 212 advwdt_close(struct inode *inode, struct file *file)
 213 {
 214         if (adv_expect_close == 42) {
 215                 advwdt_disable();
 216         } else {
 217                 printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n");
 218                 advwdt_ping();
 219         }
 220         clear_bit(0, &advwdt_is_open);
 221         adv_expect_close = 0;
 222         return 0;
 223 }
 224
 225 /*
 226  *      Kernel Interfaces
 227  */
 228
 229 static const struct file_operations advwdt_fops = {
 230         .owner          = THIS_MODULE,
 231         .llseek         = no_llseek,
 232         .write          = advwdt_write,
 233         .ioctl          = advwdt_ioctl,
 234         .open           = advwdt_open,
 235         .release        = advwdt_close,
 236 };
 237
 238 static struct miscdevice advwdt_miscdev = {
 239         .minor  = WATCHDOG_MINOR,
 240         .name   = "watchdog",
 241         .fops   = &advwdt_fops,
 242 };
 243
 244 /*
 245  *      Init & exit routines
 246  */
 247
 248 static int __devinit
 249 advwdt_probe(struct platform_device *dev)
 250 {
 251         int ret;
 252
 253         if (wdt_stop != wdt_start) {
 254                 if (!request_region(wdt_stop, 1, WATCHDOG_NAME)) {
 255                         printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
 256                                 wdt_stop);
 257                         ret = -EIO;
 258                         goto out;
 259                 }
 260         }
 261
 262         if (!request_region(wdt_start, 1, WATCHDOG_NAME)) {
 263                 printk (KERN_ERR PFX "I/O address 0x%04x already in use\n",
 264                         wdt_start);
 265                 ret = -EIO;
 266                 goto unreg_stop;
 267         }
 268
 269         /* Check that the heartbeat value is within it's range ; if not reset to the default */
 270         if (advwdt_set_heartbeat(timeout)) {
 271                 advwdt_set_heartbeat(WATCHDOG_TIMEOUT);
 272                 printk (KERN_INFO PFX "timeout value must be 1<=x<=63, using %d\n",
 273                         timeout);
 274         }
 275
 276         ret = misc_register(&advwdt_miscdev);
 277         if (ret != 0) {
 278                 printk (KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n",
 279                         WATCHDOG_MINOR, ret);
 280                 goto unreg_regions;
 281         }
 282
 283         printk (KERN_INFO PFX "initialized. timeout=%d sec (nowayout=%d)\n",
 284                 timeout, nowayout);
 285
 286 out:
 287         return ret;
 288 unreg_regions:
 289         release_region(wdt_start, 1);
 290 unreg_stop:
 291         if (wdt_stop != wdt_start)
 292                 release_region(wdt_stop, 1);
 293         goto out;
 294 }
 295
 296 static int __devexit
 297 advwdt_remove(struct platform_device *dev)
 298 {
 299         misc_deregister(&advwdt_miscdev);
 300         release_region(wdt_start,1);
 301         if(wdt_stop != wdt_start)
 302                 release_region(wdt_stop,1);
 303
 304         return 0;
 305 }
 306
 307 static void
 308 advwdt_shutdown(struct platform_device *dev)
 309 {
 310         /* Turn the WDT off if we have a soft shutdown */
 311         advwdt_disable();
 312 }
 313
 314 static struct platform_driver advwdt_driver = {
 315         .probe          = advwdt_probe,
 316         .remove         = __devexit_p(advwdt_remove),
 317         .shutdown       = advwdt_shutdown,
 318         .driver         = {
 319                 .owner  = THIS_MODULE,
 320                 .name   = DRV_NAME,
 321         },
 322 };
 323
 324 static int __init
 325 advwdt_init(void)
 326 {
 327         int err;
 328
 329         printk(KERN_INFO "WDT driver for Advantech single board computer initialising.\n");
 330
 331         err = platform_driver_register(&advwdt_driver);
 332         if (err)
 333                 return err;
 334
 335         advwdt_platform_device = platform_device_register_simple(DRV_NAME, -1, NULL, 0);
 336         if (IS_ERR(advwdt_platform_device)) {
 337                 err = PTR_ERR(advwdt_platform_device);
 338                 goto unreg_platform_driver;
 339         }
 340
 341         return 0;
 342
 343 unreg_platform_driver:
 344         platform_driver_unregister(&advwdt_driver);
 345         return err;
 346 }
 347
 348 static void __exit
 349 advwdt_exit(void)
 350 {
 351         platform_device_unregister(advwdt_platform_device);
 352         platform_driver_unregister(&advwdt_driver);
 353         printk(KERN_INFO PFX "Watchdog Module Unloaded.\n");
 354 }
 355
 356 module_init(advwdt_init);
 357 module_exit(advwdt_exit);
 358
 359 MODULE_LICENSE("GPL");
 360 MODULE_AUTHOR("Marek Michalkiewicz <marekm@linux.org.pl>");
 361 MODULE_DESCRIPTION("Advantech Single Board Computer WDT driver");
 362 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);